The　elastodynamic　dislocation　behaviors　are　of　great　interest　for　understanding　the　performances　of　structural　alloys　under　intense　dynamic　loading　conditions.The　formation,propagations,and　interactions　of　dislocations(such　as　injected　dislocation,accelerating　dislocation,steady　moving　dislocation　at　high　constant　speed)are　quite　different　from　static　dislocations.For　steady-moving　dislocation　within　the　isotropic　infinite　medium,the　effects　of　surface　and　interface　on　steady-moving　dislocations　within　limited　space　are　still　known.In　this　paper,we　in-vestigate　the　elastodynamic　image　stress　simulation　of　steady　moving　dislocation　within　film　of　limited　thickness　at　constant　speed　using　Eigenstrain　theory,Lorentz　transformation,and　steady　dynamic　equilibrium　equations.We　propose　an　efficient　solution　method　that　involves　complex　Fourier　series,transforming　partial　differential　equations　into　ordinary　differential　equations,and　ultimately　into　a　set　of　algebraic　equations　in　spectral　space.The　effects　of　dislocation　speed　and　position　near　the　free　surface　on　the　image　stress　of　steady-moving　climbing　and　gliding　dislocations　within　the　thin　film　are　examined.The　results　show　that　relativistic　effects　are　significant　for　certain　dislocation　configurations　and　stress　components,whereas　other　stress　components　are　less　sensitive　to　relativistic　effects　near　the　transonic　speed　region.